package com.gbb.common.widget;

import android.annotation.TargetApi;
import android.content.Context;
import android.content.res.TypedArray;
import android.os.Build;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CompoundButton;
import android.widget.LinearLayout;

/**
 * 支持嵌套CompoundButton的NestRadioGroup
 *
 * @author 农民伯伯 http://www.cnblogs.com/over140/
 */
public class NestRadioGroup extends LinearLayout {

    // holds the checked id; the selection is empty by default
    private int mCheckedId = -1;

    // tracks children radio buttons checked state
    private CompoundButton.OnCheckedChangeListener mChildOnCheckedChangeListener;

    // when true, mOnCheckedChangeListener discards events
    private boolean mProtectFromCheckedChange = false;

    private OnCheckedChangeListener mOnCheckedChangeListener;

    private PassThroughHierarchyChangeListener mPassThroughListener;

    /**
     * {@inheritDoc}
     */
    public NestRadioGroup(Context context) {
        super(context);
        init();
    }

    /**
     * {@inheritDoc}
     */
    public NestRadioGroup(Context context,AttributeSet attrs) {
        super(context,attrs);
        init();
    }

    private void init() {
        mCheckedId = View.NO_ID;
        setOrientation(HORIZONTAL);
        mChildOnCheckedChangeListener = new CheckedStateTracker();
        mPassThroughListener = new PassThroughHierarchyChangeListener();
        super.setOnHierarchyChangeListener(mPassThroughListener);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void setOnHierarchyChangeListener(OnHierarchyChangeListener listener) {
        // the user listener is delegated to our pass-through listener
        mPassThroughListener.mOnHierarchyChangeListener = listener;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected void onFinishInflate() {
        super.onFinishInflate();

        // checks the appropriate radio button as requested in the XML file
        if(mCheckedId != View.NO_ID) {
            mProtectFromCheckedChange = true;
            setCheckedStateForView(mCheckedId,true);
            mProtectFromCheckedChange = false;
            setCheckedId(mCheckedId);
        }
    }

    /** 递归查找具有选中属性的子控件 */
    private static CompoundButton findCheckedView(View child) {
        if(child instanceof CompoundButton) {
            return (CompoundButton)child;
        }
        if(child instanceof ViewGroup) {
            ViewGroup group = (ViewGroup)child;
            for(int i = 0, j = group.getChildCount(); i < j; i++) {
                CompoundButton check = findCheckedView(group.getChildAt(i));
                if(check != null) {
                    return check;
                }
            }
        }
        return null;// 没有找到
    }

    @Override
    public void addView(View child,int index,ViewGroup.LayoutParams params) {
        final CompoundButton view = findCheckedView(child);
        if(view != null) {
            if(view.isChecked()) {
                mProtectFromCheckedChange = true;
                if(mCheckedId != -1) {
                    setCheckedStateForView(mCheckedId,false);
                }
                mProtectFromCheckedChange = false;
                setCheckedId(view.getId());
            }
        }
        super.addView(child,index,params);
    }

    /**
     * <p>
     * Sets the selection to the radio button whose identifier is passed in
     * parameter. Using -1 as the selection identifier clears the selection;
     * such an operation is equivalent to invoking {@link #clearCheck()}.
     * </p>
     *
     * @param id the unique id of the radio button to select in this group
     * @see #getCheckedRadioButtonId()
     * @see #clearCheck()
     */
    public void check(int id) {
        // don't even bother
        if(id != -1 && (id == mCheckedId)) {
            return;
        }

        if(mCheckedId != -1) {
            setCheckedStateForView(mCheckedId,false);
        }

        if(id != -1) {
            setCheckedStateForView(id,true);
        }

        setCheckedId(id);
    }

    private void setCheckedId(int id) {
        mCheckedId = id;
        if(mOnCheckedChangeListener != null) {
            mOnCheckedChangeListener.onCheckedChanged(this,mCheckedId);
        }
    }

    private void setCheckedStateForView(int viewId,boolean checked) {
        View checkedView = findViewById(viewId);
        if(checkedView != null && checkedView instanceof CompoundButton) {
            ((CompoundButton)checkedView).setChecked(checked);
        }
    }

    /**
     * <p>
     * Returns the identifier of the selected radio button in this group. Upon
     * empty selection, the returned value is -1.
     * </p>
     *
     * @return the unique id of the selected radio button in this group
     * @attr ref android.R.styleable#NestRadioGroup_checkedButton
     * @see #check(int)
     * @see #clearCheck()
     */
    public int getCheckedRadioButtonId() {
        return mCheckedId;
    }

    /**
     * <p>
     * Clears the selection. When the selection is cleared, no radio button in
     * this group is selected and {@link #getCheckedRadioButtonId()} returns
     * null.
     * </p>
     *
     * @see #check(int)
     * @see #getCheckedRadioButtonId()
     */
    public void clearCheck() {
        check(-1);
    }

    /**
     * <p>
     * Register a callback to be invoked when the checked radio button changes
     * in this group.
     * </p>
     *
     * @param listener the callback to call on checked state change
     */
    public void setOnCheckedChangeListener(OnCheckedChangeListener listener) {
        mOnCheckedChangeListener = listener;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public LayoutParams generateLayoutParams(AttributeSet attrs) {
        return new NestRadioGroup.LayoutParams(getContext(),attrs);
    }

    /**
     * {@inheritDoc}
     */
    @Override
    protected boolean checkLayoutParams(ViewGroup.LayoutParams p) {
        return p instanceof NestRadioGroup.LayoutParams;
    }

    @Override
    protected LinearLayout.LayoutParams generateDefaultLayoutParams() {
        return new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
    }

    /**
     * <p>
     * This set of layout parameters defaults the width and the height of the
     * children to {@link #WRAP_CONTENT} when they are not specified in the XML
     * file. Otherwise, this class ussed the value read from the XML file.
     * </p>
     * <p>
     * Attributes} for a list of all child view attributes that this class
     * supports.
     * </p>
     */
    public static class LayoutParams extends LinearLayout.LayoutParams {

        /**
         * {@inheritDoc}
         */
        public LayoutParams(Context c,AttributeSet attrs) {
            super(c,attrs);
        }

        /**
         * {@inheritDoc}
         */
        public LayoutParams(int w,int h) {
            super(w,h);
        }

        /**
         * {@inheritDoc}
         */
        public LayoutParams(int w,int h,float initWeight) {
            super(w,h,initWeight);
        }

        /**
         * {@inheritDoc}
         */
        public LayoutParams(ViewGroup.LayoutParams p) {
            super(p);
        }

        /**
         * {@inheritDoc}
         */
        public LayoutParams(MarginLayoutParams source) {
            super(source);
        }

        /**
         * <p>
         * Fixes the child's width to
         * {@link android.view.ViewGroup.LayoutParams#WRAP_CONTENT} and the
         * child's height to
         * {@link android.view.ViewGroup.LayoutParams#WRAP_CONTENT} when not
         * specified in the XML file.
         * </p>
         *
         * @param a the styled attributes set
         * @param widthAttr the width attribute to fetch
         * @param heightAttr the height attribute to fetch
         */
        @Override
        protected void setBaseAttributes(TypedArray a,int widthAttr,int heightAttr) {

            if(a.hasValue(widthAttr)) {
                width = a.getLayoutDimension(widthAttr,"layout_width");
            } else {
                width = WRAP_CONTENT;
            }

            if(a.hasValue(heightAttr)) {
                height = a.getLayoutDimension(heightAttr,"layout_height");
            } else {
                height = WRAP_CONTENT;
            }
        }
    }


    /**
     * <p>
     * Interface definition for a callback to be invoked when the checked radio
     * button changed in this group.
     * </p>
     */
    public interface OnCheckedChangeListener {

        /**
         * <p>
         * Called when the checked radio button has changed. When the selection
         * is cleared, checkedId is -1.
         * </p>
         *
         * @param group the group in which the checked radio button has changed
         * @param checkedId the unique identifier of the newly checked radio
         * button
         */
        public void onCheckedChanged(NestRadioGroup group,int checkedId);
    }


    private class CheckedStateTracker implements CompoundButton.OnCheckedChangeListener {

        @Override
        public void onCheckedChanged(CompoundButton buttonView,boolean isChecked) {
            // prevents from infinite recursion
            if(mProtectFromCheckedChange) {
                return;
            }

            mProtectFromCheckedChange = true;
            if(mCheckedId != -1) {
                setCheckedStateForView(mCheckedId,false);
            }
            mProtectFromCheckedChange = false;

            int id = buttonView.getId();
            setCheckedId(id);
        }
    }


    /**
     * <p>
     * A pass-through listener acts upon the events and dispatches them to
     * another listener. This allows the table layout to set its own internal
     * hierarchy change listener without preventing the user to setup his.
     * </p>
     */
    private class PassThroughHierarchyChangeListener implements ViewGroup.OnHierarchyChangeListener {

        private ViewGroup.OnHierarchyChangeListener mOnHierarchyChangeListener;

        @Override
        @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)
        public void onChildViewAdded(View parent,View child) {
            if(parent == NestRadioGroup.this) {
                // 查找子控件
                CompoundButton view = findCheckedView(child);
                if(view != null) {
                    int id = view.getId();
                    // generates an id if it's missing
                    if(id == View.NO_ID && Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
                        id = View.generateViewId();
                        view.setId(id);
                    }
                    view.setOnCheckedChangeListener(mChildOnCheckedChangeListener);
                }
            }

            if(mOnHierarchyChangeListener != null) {
                mOnHierarchyChangeListener.onChildViewAdded(parent,child);
            }
        }

        @Override
        public void onChildViewRemoved(View parent,View child) {
            if(parent == NestRadioGroup.this) {
                // 查找子控件
                CompoundButton view = findCheckedView(child);
                if(view != null) {
                    view.setOnCheckedChangeListener(null);
                }
            }

            if(mOnHierarchyChangeListener != null) {
                mOnHierarchyChangeListener.onChildViewRemoved(parent,child);
            }
        }
    }
}